JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III Year SCIENCE AND TECHNOLOGY OF NANO MATERIALS Previous Question Paper (November/December - 2020 - R16)

Nanomaterials exhibit exceptional catalytic activity due to their high surface-to-volume ratio, which provides a significantly larger number of active sites for chemical reactions compared to bulk materials. The unique electronic structure and surface morphology at the nanoscale allow for enhanced reaction rates, selectivity, and efficiency.

• Increased Surface Area: As particle size decreases, the fraction of atoms located on the surface increases dramatically. This ensures that more reactant molecules can be adsorbed and transformed into products.
• Electronic Effects: Quantum confinement effects alter the density of states near the Fermi level, which modifies the binding energy of reactants to the catalyst surface, thereby lowering the activation energy of the reaction.
• Selectivity: The precise control over the shape and facet orientation of nanocatalysts allows for high selectivity in complex chemical processes, such as the synthesis of fine chemicals or fuel cell reactions.
• Applications: Nanocatalysts are widely used in photocatalysis (e.g., TiO2 for water splitting and degradation of pollutants), electrocatalysis (e.g., Pt-based nanoparticles in PEM fuel cells), and industrial hydrogenation/oxidation processes.

The integration of nanomaterials into mainstream technology faces several critical challenges, while simultaneously offering transformative future prospects.

Challenges:

• Toxicity and Environmental Impact: The small size of nanomaterials allows them to penetrate biological barriers, raising concerns regarding their long-term health effects and environmental persistence.
• Scalability and Cost: Developing cost-effective, large-scale manufacturing processes that maintain uniform size and shape control remains a significant hurdle for industrial adoption.
• Characterization and Standardization: The lack of standardized protocols for measuring and characterizing nanomaterial properties leads to inconsistencies in research data and safety assessments.
• Stability: Nanoparticles are prone to aggregation and oxidation, which can lead to a loss of their unique properties over time.

Future Prospects:

• Nanomedicine: Advances in targeted drug delivery systems and non-invasive diagnostic imaging tools are expected to revolutionize personalized healthcare.
• Energy Storage: Development of high-capacity nanostructured electrodes for batteries and supercapacitors will enable more efficient energy storage solutions for electric vehicles and renewable energy grids.
• Sustainable Environment: Nanomaterials will play a pivotal role in advanced water purification membranes and efficient carbon capture technologies.
• Nanoelectronics: The transition from silicon-based transistors to carbon nanotube or graphene-based devices promises faster, smaller, and more energy-efficient computing systems.